What it is and what it does
The Siemens 3VA2225-5HN42-0BH0 is a SENTRON molded case circuit breaker (MCCB) rated for a continuous current of 250 A, with four poles and an ETU350 electronic trip unit configured for line protection. It carries an undervoltage release (UVR) as the auxiliary release design, plus two auxiliary switches and one trip alarm switch (HQ configuration). The breaking capacity reaches 187 kA at 240 V, 121 kA at 415/440 V, 79 kA at 500 V, and 5.1 kA at 690 V — so it can interrupt high fault currents on a 240 V secondary side, but the 690 V rating is modest and governs selectivity planning on higher-voltage distribution.
Thermal derating and panel fit
The 250 A rating holds flat up to 50 °C ambient; above that it derates to 241 A at 55 °C, 232 A at 60 °C, 222 A at 65 °C, and 213 A at 70 °C. In a warm enclosure — say a non-ventilated panel near a process oven — plan for the derated figure, not the nameplate 250 A. The housing measures 86 mm deep by 140 mm wide by 181 mm high, which fits standard SENTRON 3VA panel cutouts and busbar spacing.